Effect of the interaction mode of H2O2 over CuMnO2 surface on •OH generation for efficient degradation of ofloxacin: Activity and mechanism

Most researches focus on design and optimization of heterogeneous Fenton catalyst itself to drive H2O2 decomposition into •OH radicals. In this study, we reported the significant impact of the interaction mode of H2O2 and CuMnO2 (namely H2O2 occurrence form) on the Fenton-like performance. The interaction mode of H2O2 largely exposed to Cu atom active site (CMH-L) led to a superior ofloxacin (OFX) degradation efficiency of 93% compared with H2O2 middle exposed around the Cu atoms (CMH-M, 84%) and small part exposed around the Cu atoms (CMH-S, 50%). The effect of H2O2 occurrence forms on catalytic activity were confirmed by analyzing their fraction and the relevant rate constant with the correlation was 98%. And the relevant interfacial reaction mechanism was detailed explored based on density functional theory calculation, a series of probe experiments and quantitative analysis of H2O2 utilization efficiency and •OH generation. It revealed that Cu atom arrangement on CuMnO2 can induce the different H2O2 occurrence form, and compared with CMH-M especially CMH-S (1.486 and 1.591 Å), CMH-L has the shortest elongation of O-O bond (1.477 vs. 1.468 Å in free H2O2) together with the smallest O-H1 and O-H2 (0.988, 1.022 Å), which were more likely to decomposition H2O2 into •OH, while it was more likely to inefficient transformation H2O2 into O2 in CMH-S system. Thus, this work provided a new insight for improving the heterogeneous Fenton catalytic performance via altering the interaction mode of H2O2 and catalyst, which should be the fundamental reason for efficient H2O2 activation into O2 or •OH.